FIG 11.

IFN treatment triggers apoptosis of IBDV-infected chicken DF-1 cells. DF-1 cells were infected with IBDV (MOI of 2) and treated or not with 1,000 U/ml of chIFN-α at 3 h p.i. Mock-infected (M and M+3) and IBDV-infected (I and I+3) cells were analyzed at 16 h p.i. (A) Cells were incubated with the IncuCyte caspase 3/7 apoptosis assay reagent, and images were recorded with an IncuCyte Zoom system apparatus at 16 h p.i. Apoptotic cells are green. (B) Apoptosis measurement. As a control for apoptosis, uninfected DF-1 cells were treated with different doses of staurosporine (0.5, 1, and 2 μM) for 16 h. Apoptosis in duplicate samples was measured by using the Caspase-Glo 3/7 assay kit, and each determination was carried out in duplicate. Caspase values for infected cell samples were normalized to those for mock-infected cells. Bars indicate means ± standard deviations based on data from duplicate samples from two independent experiments. ** indicates a P value of <0.01, as determined by unpaired Student's t test.